Potential Port Monitor or Print Processor Registration Abuse

Identifies port monitor and print processor registry modifications. Adversaries may abuse port monitor and print processors to run malicious DLLs during system boot that will be executed as SYSTEM for privilege escalation and/or persistence, if permissions allow writing a fully-qualified pathname for that DLL.

Rule type: eql

Rule indices:

logs-endpoint.events.*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

https://www.welivesecurity.com/2020/05/21/no-game-over-winnti-group/

Tags:

Elastic
Host
Windows
Threat Detection
Privilege Escalation

Version: 2

Rule authors:

Elastic

Rule license: Elastic License v2

Rule query

edit

registry where event.type in ("creation", "change") and
  registry.path : ("HKLM\\SYSTEM\\*ControlSet*\\Control\\Print\\Monitors\\*",
    "HKLM\\SYSTEM\\*ControlSet*\\Control\\Print\\Environments\\Windows*\\Print Processors\\*") and
  registry.data.strings : "*.dll" and
  /* exclude SYSTEM SID - look for changes by non-SYSTEM user */
  not user.id : "S-1-5-18"

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Privilege Escalation
- ID: TA0004
- Reference URL: https://attack.mitre.org/tactics/TA0004/
Technique:
- Name: Boot or Logon Autostart Execution
- ID: T1547
- Reference URL: https://attack.mitre.org/techniques/T1547/
Sub-technique:
- Name: Port Monitors
- ID: T1547.010
- Reference URL: https://attack.mitre.org/techniques/T1547/010/
Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
Technique:
- Name: Boot or Logon Autostart Execution
- ID: T1547
- Reference URL: https://attack.mitre.org/techniques/T1547/
Sub-technique:
- Name: Port Monitors
- ID: T1547.010
- Reference URL: https://attack.mitre.org/techniques/T1547/010/

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